Tape heads may be used to tape closed the flaps of cases (e.g., cardboard boxes) moving down a conveyor system. In one example, the bottom of a case may be sealed with tape, the case may be filled with product (e.g., cans of soup, packaged consumer goods or anything else), and the top of the case may be sealed. In such an example, the sealing involves placement of a piece of tape along an area wherein the two flaps meet, so that approximately half the width of the tape is attached to each flap. Significantly, the piece of tape may be longer than a length of the flaps, so that each end of the tape bends 90 degrees and terminates in a position on a side of the case.
A tape head typically holds a spool of tape, which may include an unrolled end that may be guided by one or more guide rollers. The end of the tape may be positioned so that a first application roller causes the end to touch or contact a leading side of a case moving down the conveyor. As the case advances, the first application roller presses the tape into contact with the leading side of the case. As the case advances further, the first application roller may wrap around an edge of the case, thereby bringing the tape into contact with the adjacent flaps. In the example wherein the top of the case is being sealed, the advancing case pushes the first application roller upwardly and around the edge of the case. As the case advances further, tape is pressed into contact with both flaps by the first application roller.
As the case continues to advance, the case moves past the first application roller, and contact between the first application roller and the case terminates. At this point, the first application roller has pressed the tape against the full length of the joined flaps. The tape is cut at a length sufficient to fully tape together the flaps and also to wrap around the edge of the case. After the first application roller loses contact with the case, a second application roller continues to press the tape against the joined flaps. As the edge of the case begins to pass the second application roller, the second application roller moves around the edge of the case and presses the cut end of the tape against the trailing side of the case. The energy to move the second application roller around the edge of the case and against the trailing side of the case is obtained from allowing a spring—which was tensioned upon contact of the moving case with the first application roller—to relax.